diff --git a/libavcodec/flacdec.c b/libavcodec/flacdec.c
index da4d770aba..969fa8e1ac 100644
--- a/libavcodec/flacdec.c
+++ b/libavcodec/flacdec.c
@@ -406,7 +406,7 @@ static inline int decode_subframe(FLACContext *s, int channel)
     if (wasted) {
         int i;
         for (i = 0; i < s->blocksize; i++)
-            decoded[i] <<= wasted;
+            decoded[i] = (unsigned)decoded[i] << wasted;
     }
 
     return 0;